Giuseppina Scano

Human mitochondrial DNA variation in Southern Italy

Background: Since prehistoric times Southern Italy has been a cultural crossroads of the Mediterranean basin. Genetic data on the peoples of Basilicata and Calabria are scarce and, particularly, no records on mtDNA variability have been published. Aim: In this study mtDNA haplotypes of populations from Basilicata, Calabria and Sicily are compared with those of other Italian and Mediterranean populations, so as to investigate their genetic relationships. Subjects and methods: A total of 341 individuals was analysed for mtDNA in order to provide their classification into haplogroups. Multivariate analysis was used to compare the studied populations with other Mediterranean samples; median-joining network analysis was applied to observe the relationship between the major lineages of the Southern Italians. Results: The haplogroup distribution in the Southern Italian samples falls within the typical pattern of mtDNA variability of Western Eurasia. The comparison with other Mediterranean countries showed a substantial homogeneity of the area, which is probably related to the historic contact through the Mediterranean Sea. Conclusion: The mtDNA analysis demonstrated that Southern Italy displays a typical pattern of Mediterranean basin variability, even though it appears plausible that Southern Italy was less affected by the effects of the Late Glacial Maximum, which reduced genetic diversity in Europe.

An anthropogenetic study on the Oromo and Amhara of central Ethiopia

Blood samples from members of the Oromo and Amhara ethnic groups of central Ethiopia were tested for 10 erythrocyte protein systems: ACP1, ADA, AK1, CA2, ESD, G6PD, GLO1, HBβ, PGD, and PGM1. Differences between the two samples were relatively slight and not statistically significant. Gene frequency distributions were then analyzed in the context of the genetics of the African and Arabian peoples. Considering the erythrocyte enzyme data, the Oromo and Amhara appear quite similar to Europoids (particularly to the South Arabians) and considerably different from the Negritic peoples. There is evidence for close genetic affinity among the Cushitic‐ and Semitic‐speaking population groups of the Horn. Admixture between Europoid and Negritic populations seems to have been the main microevolutionary factor in generating the present day Cushitic (and Semitic)‐speaking group of eastern Africa. The results are consistent with the hypothesis, supported by historical and linguistic evidence, for a common origin of these groups from a Cushitic‐speaking group living in eastern Africa.

Red-Cell Enzyme Polymorphisms in the Reggio Calabria Province (Italy)

Acid phosphatase (ACP1), adenosine deaminase (ADA), esterase D (ESD), glyoxalase 1 (GLO1), phosphogluconate dehydrogenase (PGD) and phosphoglucomutase 1 and 2 (PGM1 and PGM2) polymorphisms have been studied in the Reggio Calabria province (Southern Italy). The ACP1*A allele and ADA, GLO1, PGD and PGM1 systems have frequencies similar to those reported for Sicily and Southern Italy.

COL1A2 (type I collagen) polymorphisms in the Colorado Indians of Ecuador.

Background: EcoRI, MspI and RsaI restriction fragment length polymorphisms (RFLPs) of the COL1A2 (type I collagen) gene are proving to be extremely informative markers for describing human populations; therefore they hold considerable potential for anthropogenetic research. Aim: The objective of this study was to characterize at the DNA level the Colorado Indians from Ecuador, for whom only blood group frequency information is available, and to investigate their relationships with the Cayapa—another Ecuadoran Native American group belonging to the same linguistic affiliation—and other world populations. Subjects and methods: Colorado Indians (n = 80) were analysed for the three anthropologically informative RFLPs of the COL1A2 gene. To better define the genetic relationship between this group and other populations, principal component analysis (PCA) was performed and genetic distances were estimated. Population genetic structure was tested through analysis of molecular variance (AMOVA) by comparing haplotype frequencies. Results: COL1A2 allele and haplotype frequencies showed a certain degree of heterogeneity between the two Chibchan populations of Ecuador. The AMOVA test detected a significant level of differentiation (Fst = 0.034, p = 0.0049) between Colorado and Cayapa Indians. PC and genetic distance analyses showed a clear-cut separation between African and non-African populations; within the latter, the two Native American groups were differentiated from each other. Conclusions: The present findings suggest the presence of a low level of genetic relatedness between the Colorado and the Cayapa, despite their supposed common ethnogenesis. This confirms what has been inferred from other genetic data about the high degree of heterogeneity among Native Americans, even within the same linguistic branch, thus supporting the existence of genetic sub-structure within the central and southern American populations. Résumé. Arrière plan: Les polymorphismes de longueurs de fragments de restriction (RFLP) du gène COL1A2 (collagène de type 1) apparaissent comme des marqueurs humains extrêmement informatifs; ils présentent donc un intérêt potentiel considérable pour les recherches d’anthropogénétique. But: Cette étude caractérise le niveau d’ADN des indiens Colorado de l’Equateur, pour lesquels est seulement disponible l’information sur les fréquences des groupes sanguins, et examine leur relation avec un autre groupe amérindien d’Equateur de même affiliation linguistique, les indiens Cayapa, ainsi qu’avec d’autres populations. Sujets et méthodes: 80 indiens Colorado ont été analysés par rapport aux trois RFLP du gène COL1A2 anthropologiquement informatifs. Afin de mieux définir les relations génétiques de ce groupe avec d’autres populations, on a effectué une analyse en composantes principales et estimé des distances génétiques. La structure génétique de la population a été éprouvée par analyse de variance moléculaire (AMOVA) en comparant les fréquences haplotypiques. Résultats: L’allèle COLA12 et les fréquences haplotypiques indiquent un certain degré d’hétérogénéité des deux populations Chibchan d’Equateur. Le test AMOVA détecte un niveau significatif de différenciation (Fst = 0,034 p = 0.0049) entre indiens Colorado et Cayapa. Les analyses de CP et de distances génétiques montrent une séparation nette entre populations africaines et non africaines. Parmi ces dernières, les deux groupes amérindiens se séparent l’un de l’autre. Conclusion: Ces résultats suggèrent une relation génétique faible entre Colorado et Cayapa, en dépit de leur ethnogenèse supposée commune. Ils confirment ce qui a été inféré à partir d’autres données génétiques, concernant le haut degré d’hétérogénéité des amérindiens, même au sein d’une même branche linguistique, ce qui soutient l’hypothèse de l’existence d’une sous structure génétique dans les populations amérindiennes du centre et du sud des continents américains. Zusammenfassung. Hintergrund: EcoRI-, MspI- und RsaI-Restriktionsfragmentlängen-Polymorphismen (restriction fragment length polymorphisms, RFLPs) des COL1A2-(Typ I-Kollagen)-Gens erweisen sich als besonders informative Marker, um menschliche Populationen zu beschreiben; dadurch haben sie ein beträchtliches Potenzial für anthropogenetische Untersuchungen. Ziel: Das Ziel dieser Studie war, Colorado-Indianer aus Ecuador, für die nur Information betreffend Blutgruppenhäufigkeit vorhanden ist, auf DNS-Ebene zu charakterisieren und ihre Beziehung mit den Cayapa – einer anderen eingeborenen Amerikanischen Bevölkerung Ecuadors, die miteinander sprachlich verwandt sind – und anderen Populationen dieser Welt zu untersuchen. Probanden und Methoden: Colorado-Indianer (n = 80) wurden betreffend drei anthropologisch informative RFLPs des COL1A2-Gens untersucht. Um die genetische Beziehung zwischen dieser Gruppe und anderen Populationen besser definieren zu können, wurden Hauptkomponenten-Analysen (principal component analysis, PCA) gerechnet und genetische Distanzen bestimmt. Die genetische Struktur der Population wurde mittels einer Analyse der molekularen Varianz (analysis of molecular variance, AMOVA) durch Vergleich von Haplotyp-Häufigkeiten getestet. Ergebnisse: COL1A2-Allel- und Haplotyp-Häufigkeiten zeigten ein gewisses Maß an Heterogenität zwischen den beiden Chibchan Populationen aus Ecuador. Der AMOVA-Test zeigte einen signifikanten Unterschied (Fst = 0,034, p = 0,0049) zwischen Colorado- und Cayapa-Indianern. Hauptkomponenten-Analysen und die Analyse der genetischen Distanz zeigten eine klare Trennung zwischen Afrikanern und nicht-Afrikanischen Populationen; bei den letzteren ließen sich die beiden eingeborenen Amerikanischen Populationen voneinander unterscheiden. Zusammenfassung: Die vorliegenden Ergebnisse legen nahe, dass zwischen den Colorado und den Cayapa, trotz ihres bisher vermuteten gemeinsamen ethnischen Ursprungs, nur ein niedriges Ausmaß an genetischer Verwandtschaft besteht. Das bestätigt, was schon aus anderen genetischen Untersuchungsbefunden über den hohen Grad an Heterogenität unter eingeborenen Amerikanischen Völkern – selbst innerhalb derselben Sprachenfamilie – geschlossen worden ist, und bestätigt damit das Vorhandensein von genetischen Unterstrukturen bei Mittel- und Südamerikanischen Völkern. Resumen. Antecedentes: Se ha comprobado que los polimorfismos de longitud de los fragmentos de restricción (RFLPs) EcoRI, MspI y RsaI, son marcadores muy informativos para describir a las poblaciones humanas; por tanto, tienen un potencial considerable para la investigación antropogenética. Objetivos: El objetivo de este estudio fue caracterizar a nivel del ADN a los indios Colorado de Ecuador, de los que solo se dispone de información sobre las frecuencias de grupos sanguíneos, e investigar sus relaciones con los Cayapa, otro grupo Americano nativo de Ecuador que pertenece al mismo grupo lingüístico, y con otras poblaciones mundiales. Sujetos y métodos: Se analizaron indios Colorado (n = 80) para los tres RFLPs del gen COL1A2, antropológicamente informativos. Para definir mejor la relación genética entre este grupo y otras poblaciones, se realizó un análisis en componentes principales (ACP) y se estimaron las distancias genéticas. La estructura genética de la población se comprobó mediante un análisis molecular de la varianza (AMOVA) comparando frecuencias de haplotipos. Resultados: El alelo COL1A2 y las frecuencias haplotípicas mostraron un cierto grado de heterogeneidad entre las dos poblaciones Chibchan de Ecuador. El test AMOVA detectó un nivel de diferenciación significativo (Fst = 0,034, p = 0,0049) entre los indios Colorado y Cayapa. Los análisis PC y de distancia genética mostraron una separación neta entre las poblaciones Africanas y no Africanas; dentro de estas últimas, los análisis diferenciaron a los dos grupos Americanos nativos. Conclusión: Los resultados actuales sugieren la presencia de un bajo nivel de relación genética entre los indios Colorado y los Cayapa, a pesar de su supuesta etnogénesis común. Esto confirma lo ya inferido a partir de otros datos genéticos sobre el elevado grado de heterogeneidad entre los Americanos nativos, incluso dentro de la misma rama lingüística, y apoya la existencia de una subestructura genética dentro de las poblaciones centroamericanas y sudamericanas.

Linking between genetic structure and geographical distance: Study of the maternal gene pool in the Ethiopian population

Abstract Background The correlation between genetics and geographical distance has already been examined through the study of the dispersion of human populations, especially in terms of uniparental genetic markers. Aim The present work characterises, at the level of the mitochondrial DNA (mtDNA), two new samples of Amhara and Oromo populations from Ethiopia to evaluate the possible pattern of distribution for mtDNA variation and to test the hypothesis of the Isolation-by-Distance (IBD) model among African, European and Middle-Eastern populations. Subjects and methods This study analysed 173 individuals belonging to two ethnic groups of Ethiopia, Amhara and Oromo, by assaying HVS-I and HVS-II of mtDNA D-loop and informative coding region SNPs of mtDNA. Results The analysis suggests a relationship between genetic and geographic distances, affirming that the mtDNA pool of Africa, Europe and the Middle East might be coherent with the IBD model. Moreover, the mtDNA gene pools of the Sub-Saharan African and Mediterranean populations were very different. Conclusion In this study the pattern of mtDNA distribution, beginning with the Ethiopian plateau, was tested in the IBD model. It could be affirmed that, on a continent scale, the mtDNA pool of Africa, Europe and the Middle East might fall under the IBD model.

Mitochondrial variability in the Mediterranean area: a complex stage for human migrations

Abstract Context: The Mediterranean area has always played a significant role in human dispersal due to the large number of migratory events contributing to shape the cultural features and the genetic pool of its populations. Objective: This paper aims to review and diachronically describe the mitogenome variability in the Mediterranean population and the main demic diffusions that occurred in this area over time. Methods: Frequency distributions of the leading mitochondrial haplogroups have been geographically and chronologically evaluated. The variability of U5b and K lineages has been focussed to broaden the knowledge of their genetic histories. Results: The mitochondrial genetic makeup of Palaeolithic hunter-gatherers is poorly defined within the extant Mediterranean populations, since only a few traces of their genetic contribution are still detectable. The Neolithic lineages are more represented, suggesting that the Neolithic revolution had a marked effect on the peopling of the Mediterranean area. The largest effect, however, was provided by historical migrations. Conclusion: Although the mitogenome variability has been widely used to try and clarify the evolution of the Mediterranean genetic makeup throughout almost 50 000 years, it is necessary to collect whole genome data on both extinct and extant populations from this area to fully reconstruct and interpret the impact of multiple migratory waves and their cultural and genetic consequences on the structure of the Mediterranean populations.

Variability and distribution of COL1A2 (type I collagen)polymorphisms in the central-eastern Mediterranean Basin

Abstract Background: The most abundant of the collagen protein family, type I collagen is encoded by the COL1A2 gene. The COL1A2 restriction fragment length polymorphisms (RFLPs) EcoRI, RsaI and MspI in samples from several different central-eastern Mediterranean populations were analysed and found to be potentially informative anthropogenetic markers. Aim: The objective was to define the genetic variability of COL1A2 in the central-eastern Mediterranean and to shed light on its genetic distribution in human groups over a wide geographic area. Subjects and methods: PCR-RFLP analysis of EcoRI, RsaI and MspI polymorphisms of the COL1A2 gene was performed on oral swab and blood samples from 308 individuals from the central-eastern Mediterranean Basin. The genetic similarities among these groups and other populations described in the literature were investigated through correspondence analysis. Results: Single-marker data and haplotype frequencies seemed to suggest a genetic homogeneity within the European populations, whereas a certain degree of differentiation was noted for the Egyptians and the Turks. Conclusions: The genetic variability in the central-eastern Mediterranean area is probably a result of the geographical barrier of the Mediterranean Sea, which separated European and African populations over time.

Explorative genetic association study of GSTT2B copy number variant in complex disease risks

Abstract Background: Glutathione S-transferases (GSTs) are the main phase II enzymes involved in cellular detoxification. Through phase I and phase II detoxification reactions, the cell is able to detoxify endogenous and exogenous toxic compounds. Aims: This study focused attention on the GSTT2B copy number variant (CNV) in order to explore its involvement in the genetic pre-disposition to asthma, Alzheimers disease (AD), allergic rhinitis (AR), essential hypertension (EH), hypothyroidism and recurrent miscarriage (RM). Methods: The study population consists of 1225 individuals divided into six case-control groups. The genotyping of the GSTT2B CNV was performed by using a duplex-PCR. Odds Ratios (ORs) were calculated, adjusting for the confounding variables, to estimate the association between GSTT2B CNV and the disease status. Results: The χ2-test and ORs did not show any association between this genetic marker and pathological phenotypes. Conclusion: The data highlights that GSTT2B CNV is not associated with the investigated complex diseases in Italian patients. However, further investigations are necessary to replicate these findings in larger sample sizes and to explore other health-related phenotypes.